An accumulation of snow is usually removed from pavement by a truck that is provided with a snow plow having a moldboard mounted on the front end of the truck. Typically, the plowing operation leaves some amount of snow or ice or slush on the pavement being cleared. When the snow or ice is packed down on the pavement surface, the ability of the moldboard to remove all or substantially all of the snow and ice is significantly reduced.
During a plowing operation, it is conventional to raise and lower the moldboard of the snow plow as desired and to change the angle that the moldboard of the snow plow makes with the longitudinal center axis of the truck, and therefore with respect to the longitudinal axis of the lane of pavement being cleared.
The moldboard of the snow plow may be selectively raised and lowered so that the plow truck may be driven with the lowermost edge of the moldboard either in contact (for conducting a plowing operation) or out of contact with the road, such as when the truck is being driven over pavement which has already been cleared of snow. Also, the snow plow is typically arranged to enable the angle of the plow with respect to the truck to be changed so that the snow plow can be used to divert snow to the left or to the right of the truck or used to push snow directly in front of the truck such as when clearing a driveway or parking lot.
A wing plow or another attachment may be provided to effectively extend the width of the lane that can be plowed by a single truck in a single pass. Such wing plows are typically mounted at one side of the truck. Snow plow vehicles at airfields may sometimes have a front plow blade and a broom which is towed by the vehicle.
In U.S. Pat. No. 7,730,643, a Two-Stage Snow Plow is disclosed. In a preferred embodiment of that patent, a secondary plow is provided behind a main snow plow or moldboard, with the secondary plow formed of a plurality of resilient fingers. The secondary plow typically removes snow and ice that has been packed down onto the pavement and is difficult to remove with the main snow plow. In certain preferred embodiments, the secondary plow is configured to allow translation of the secondary plow relative to the main plow in a direction that is substantially parallel to the main plow scraping edge so that left and right ends of the secondary plow are substantially aligned with the respective left and right ends of the main plow.
The finger plow of U.S. Pat. No. 7,730,643 can be mounted in various positions on a vehicle. For example, the finger plow may be fixedly mounted underneath the chassis of a truck between the front and rear wheels. In that arrangement, the finger plow is preferably actuated by a hydraulic cylinder that raises the fingers out of engagement with the pavement and lowers the fingers into engagement with the pavement during plowing operations.
Especially when the finger plow is fixedly mounted beneath a truck, it is desirable to not have the ends of the finger plow extend significantly beyond the outermost edges of the tires of the vehicle. As a result, in such an arrangement, the secondary plow tends to discharge snow and ice adjacent or substantially in the path of the wheels of the vehicle, especially when a snow removing truck with a finger plow deployed is moving slowly in heavy traffic or is moving in an urban area where the snow and ice may remain on the pavement and be packed down by the wheels of the vehicle or by other vehicles.
The need remains for a finger plow arrangement in which the snow and ice which is removed from the pavement by the finger plow is discharged away from the vehicle so that the snow and ice is unlikely to be packed down by the wheels of the vehicle and wherein the finger plow may be configured so as not to extend substantially beyond the outermost edges of the vehicle when the finger plow is not engaged in a plowing operation.